1. Technical Field
This invention relates, generally, to golf clubs and, in particular, to an improved metal wood-type golf club.
2. Background Information
Modern wood-type golf club heads almost exclusively consist of a hollow metallic club head fixed to a shaft via a hosel that is rigidly attached (or integral with) the club head body. When the club head face strikes a golf ball, the various walls of the club head body experience an impulse response. For example, the top wall of the club body experiences a response characterized by the propagation of one or more waves across its surface. Because of the configuration of the hosel with respect to the club head body in traditional wood-type club heads, including the rigid attachment of the hosel to the top wall, the resulting wave propagation in prior art golf clubs is unsatisfactory and results in a significant loss of energy and, necessarily, the club head's coefficient of restitution.
As is known in the art, the coefficient of restitution (or “COR”) is used to characterize the efficiency of impact between two bodies (e.g., a golf club head and a golf ball). The COR quantifies the extent to which an impact is elastic by comparing the total energy of the colliding bodies before and after a collision. A perfectly elastic collision, for example (with no energy loss), would exhibit a COR of 1.0.
In this regard, the United States Golf Association (USGA) has promulgated rules that limit the COR for certain club heads. See, e.g., USGA Rule 4-1(a), Appendix II, and “USGA Procedure for Measuring the Velocity Ratio of a Club Head,” rev. 2 (February 1999), the contents of which are hereby incorporated by reference.
Regardless of whether a particular club head is subject to a maximum permissible COR, it is desirable to achieve a suitably high COR without compromising other design goals. Some prior art wood-type club heads are unsatisfactory in this respect as their hosel configurations tend to increase energy loss, thereby reducing their effective COR.